PCBs in indoor air and human blood in Pittsfield, Massachusetts

Effects of mixtures of polychlorinated biphenyls (PCBs) and three organochlorine pesticides on cognitive function differ between older Mohawks at Akwesasne and older adults in NHANES

BACKGROUND

Akwesasne Mohawks has been exposed to high concentrations of polychlorinated biphenyls (PCBs) and background levels of organochlorine pesticides, hexachlorobenzene (HCB), dichlorodiphenyl dichloroethylene (DDE), and mirex. We have previously reported relative contributions to the mixture of low- and high-chlorinated PCBs, HCB, and DDE on cognitive decrements in Mohawks of various ages.

OBJECTIVE

This study examines differences in the mixture effects of PCB congener groups, HCB, DDE, and mirex on cognitive function in older Mohawks and less PCB-exposed older adults from the National Health and Nutrition Examination Survey (NHANES) 1999-2002 cycles.

METHODS

We used Bayesian kernel machine regression (BKMR) to evaluate the mixture effects of different PCB congener groups, HCB, DDE, and mirex on cognitive function in both populations. Models were adjusted for age, sex, education levels, and race/ethnicity focusing on individuals 60 years and older.

RESULTS

Older Mohawks had 3-fold higher mean total PCB concentrations and 1.8-fold higher mirex, but slightly lower mean DDE and HCB levels than NHANES older adults. Higher mixture concentrations were significantly associated with greater cognitive decline. In older Mohawks, low- and high-chlorinated PCBs, HCB, and DDE contributed to the cognitive score decline. In contrast, score decline in older NHANES adults were primarily from high-chlorinated PCBs and DDE with a threshold dose of approximately 2.08-2.27 ng/g and 2.02-2.40 ng/g, respectively.

CONCLUSION

Mixtures of PCBs and organochlorine pesticides increase the risk of cognitive decline in both older Mohawks and NHANES older adults. However, contributions to these mixture effects show significant differences. In older Mohawks, high- and low-chlorinated PCBs, DDE, and HCB are the primary contributors, while high-chlorinated PCBs and DDE are important contributors in NHANES older adults. Due to chronic heavy exposures to PCBs, older Mohawks had a significantly increased risk of cognitive decline compared to general older adults from NHANES.

Airborne Pesticides-Deep Diving into Sampling and Analysis

The escalating utilization of pesticides has led to pronounced environmental contamination, posing a significant threat to agroecosystems. The extensive and persistent global application of these chemicals has been linked to a spectrum of acute and chronic human health concerns. This review paper focuses on the concentrations of airborne pesticides in both indoor and outdoor environments. The collection of diverse pesticide compounds from the atmosphere is examined, with a particular emphasis on active and passive air sampling techniques. Furthermore, a critical evaluation is conducted on the methodologies employed for the extraction and subsequent quantification of airborne pesticides. This analysis takes into consideration the complexities involved in ensuring accurate measurements, highlighting the advancements and limitations of current practices. By synthesizing these aspects, this review aims to foster a more comprehensive and informed comprehension of the intricate dynamics related to the presence and measurement of airborne pesticides. This, in turn, is poised to significantly contribute to the refinement of environmental monitoring strategies and the augmentation of precise risk assessments.

Airborne Pesticides from Agricultural Practices: A Critical Review of Pathways, Influencing Factors, and Human Health Implications

This critical review examines the release of pesticides from agricultural practices into the air, with a focus on volatilization, and the factors influencing their dispersion. The review delves into the effects of airborne pesticides on human health and their contribution to anthropogenic air pollution. It highlights the necessity of interdisciplinary research encompassing science, technology, public policy, and agricultural practices to effectively mitigate the risks associated with pesticide volatilization and spray dispersion. The text acknowledges the need for more research to understand the fate and transport of airborne pesticides, develop innovative application technologies, improve predictive modeling and risk assessment, and adopt sustainable pest management strategies. Robust policies and regulations, supported by education, training, research, and development, are crucial to ensuring the safe and sustainable use of pesticides for human health and the environment. By providing valuable insights, this review aids researchers and practitioners in devising effective and sustainable solutions for safeguarding human health and the environment from the hazards of airborne pesticides.

Investigating the effects of long-term Aroclor 1260 exposure on fatty liver disease in a diet-induced obesity mouse model

Introduction

Polychlorinated biphenyls (PCBs) are persistent environmental toxicants that have been implicated in numerous health disorders including liver diseases such as non-alcoholic fatty liver disease (NAFLD). Toxicant-associated NAFLD, also known as toxicant-associated fatty liver disease (TAFLD), consists of a spectrum of disorders ranging from steatosis and steatohepatitis to fibrosis and hepatocellular carcinoma. Previously, our group demonstrated that 12-week exposure to the PCB mixture, Aroclor 1260, exacerbated steatohepatitis in high-fat diet (HFD)-fed mice; however, the longer-term effects of PCBs on TAFLD remain to be elucidated. This study aims to examine the longer-term effects of Aroclor 1260 (>30 weeks) in a diet-induced obesity model to better understand how duration of exposure can impact TAFLD.

Methods

Male C57BL/6 mice were exposed to Aroclor 1260 (20 mg/kg) or vehicle control by oral gavage at the beginning of the study period and fed either a low-fat diet (LFD) or HFD throughout the study period.

Results

Aroclor 1260 exposure (>30 weeks) led to steatohepatitis only in LFD-fed mice. Several Aroclor 1260 exposed LFD-fed mice also developed hepatocellular carcinoma (25%), which was absent in HFD-fed mice. The LFD+Aroclor1260 group also exhibited decreased hepatic Cyp7a1 expression and increased pro-fibrotic Acta2 expression. In contrast, longer term Aroclor 1260 exposure in conjunction with HFD did not exacerbate steatosis or inflammatory responses beyond those observed with HFD alone. Further, hepatic xenobiotic receptor activation by Aroclor 1260 was absent at 31 weeks post exposure, suggesting PCB redistribution to the adipose and other extra-hepatic tissues with time.

Discussion

Overall, the results demonstrated that longer-term PCB exposure worsened TAFLD outcomes independent of HFD feeding and suggests altered energy metabolism as a potential mechanism fueling PCB mediated toxicity without dietary insult. Additional research exploring mechanisms for these longer-term PCB mediated toxicity in TAFLD is warranted.

Mixture Effects of Polychlorinated Biphenyls (PCBs) and Three Organochlorine Pesticides on Cognitive Function in Mohawk Adults at Akwesasne

The Mohawks at Akwesasne have been highly exposed to polychlorinated biphenyls (PCBs), via releases from three aluminum foundries located near the reserve. They are also exposed to organochlorine pesticides, namely hexachlorobenzene (HCB), dichlorodiphenyldichloroethylene (DDE), and mirex. Previous studies have demonstrated reduced cognition in relation to total PCBs, but the effects of the mixtures of different PCB congener groups, HCB, DDE, and mirex on cognitive function have not been studied. Therefore, cognitive performance for executive function, scored via the digit symbol substitution test (DSST), in Mohawk adults aged 17-79 years (n = 301), was assessed in relation to serum concentrations of low-chlorinated PCBs, high-chlorinated PCBs, total PCBs, HCB, DDE, and mirex. We used mixture models employing the quantile-based g-computation method. The mixture effects of low-chlorinated PCBs, high-chlorinated PCBs, HCB, DDE, and mirex were significantly associated with 4.01 DSST scores decrements in the oldest age group, 47-79 years old. There were important contributions to mixture effects from low-chlorinated PCBs, high-chlorinated PCBs, and total PCBs, with smaller contributions of HCB and DDE. Our findings indicate that exposures to both low- and high-chlorinated PCBs increase the risk of cognitive decline in older adults, while DDE and HCB have less effect.

Infant Exposure to PCBs and PBDEs Revealed by Hair and Human Milk Analysis: Evaluation of Hair as an Alternative Biomatrix

Human hair, as an emerging biological monitoring matrix, has begun to be used in various human exposure studies, but little research has been done on persistent organic pollutants (POPs), especially for the body burden of POPs in infants. In this study, 36 breast-fed infants in Shanghai were recruited for a study to determine their exposure to POPs, including 12 dioxin-like polychlorinated biphenyls (dl-PCBs), 6 indicator PCBs, and 8 polybrominated diphenyl ethers (PBDEs) in the inner layer (internal) and outer layer (external) of infant hair and human milk. The similarity or difference of the POP distribution pattern or concentration among these matrices was investigated, and only weak correlations (r < 0.4) were observed between the POP concentration in human milk and infant hair (internal or external). POPs in human milk have a different profile than those in infant hair, while they have stable concentration ratios (0.58-2.72), similar distribution patterns, fine Spearman's rank correlations, and tangled principal component analysis (PCA) plots in each POP family between external and internal hair samples. The result suggested that POPs in internal hair can be easily affected by those in external hair, but POPs in human milk seem to have little contribution to the POP profile in internal hair. Although infant hair cannot reflect the POPs from diet or from body burden, it can be an ideal biomatrix that estimates infant exposure to POPs from exogenous sources like house dust when considering the similar pattern of POPs and their proper accumulation period in hair.

Toxicity of polychlorinated biphenyls in aquatic environments - A review

The assessment of polychlorinated biphenyls (PCBs) and their congeners resulting from the pollution of all environmental media is inherently related to its persistence and ubiquitous nature. In principle, determination of this class of contaminants are limited to the determination of their concentrations in the various environmental matrices. For solving many problems in this context, knowledge of the emission sources of PCBs, transport pathways, and sites of contamination and biomagnification is of great benefit to scientists and researchers, as well as many regulatory organizations. By far the largest amounts of PCBs, regardless of their discharged points, end up in the soil, sediment and finally in different aquatic environments. By reviewing relevant published materials, the source of origin of PCBs in the environment particularly from different pollution point sources, it is possible to obtain useful information on the nature of different materials that are sources of PCBs, or their concentrations and their toxicity or health effects and how they can be removed from contaminated media. This review focuses on the sources of PCBs in aquatic environments and critically reviews the toxicity of PCBs in aquatic animals and plants. The review also assesses the toxicity equivalency factors (TEFs) of PCBs providing valuable knowledge to other scientists and researchers that enables regulatory laws to be formulated based on selective determination of concentrations regarding their maximum permissible limits (MPLs) allowed. This review also supplies a pool of valuable information useful for designing decontamination technologies for PCBs in media like soil, sediment, and wastewaters.